The prosecution alleges they started the fire last May in a botched plan to frame Philpott's ex-mistress Lisa Willis, 29, so he would win custody of their four children.

Miss Ferguson's partner Adam Taylor said Philpott told him he was worried about the custody battle when they went to buy cannabis shortly before the fire broke out.

"He was paranoid at not winning," he said.

"He was adamant that he did not want access, like weekends. He wanted full custody."

Miss Ferguson said she was surprised by the couple's "normal" behaviour when she visited them after the tragedy. "It was not the sort of behaviour you would expect from parents who had just lost six children," she said.

A few days later Philpott announced he and Mairead planned to renew their marriage vows.